In 773, Charlemagne, the king of the Franks, crossed the Alps and invaded the Lombard kingdom, which encompassed all of Italy except the Duchy of Rome, the Republic of Venice and the Byzantine possessions in the south.

The 250 to 300 lesser feudal lords of the Reichsitalien nonetheless frequently appealed to the imperial courts and jurisdiction to settle conflicts with the prominent princes.

After the Battle of Taginae, in which the Ostrogoth king Totila was killed, the Byzantine general Narses captured Rome and besieged Cumae.

[9] The Lombard kingdom proved to be more stable than its Ostrogothic predecessor, but in 774, on the pretext of defending the Papacy, it was conquered by the Franks under Charlemagne.

Following the deposition of the latter, local nobles – Guy III of Spoleto and Berengar of Friuli – disputed over the crown, and outside intervention did not cease, with Arnulf of Eastern Francia and Louis the Blind of Provence both claiming the Imperial throne for a time.

When in 960 Berengar attacked the Papal States, King Otto, summoned by Pope John XII, conquered the Italian kingdom and on 2 February 962 had himself crowned Holy Roman Emperor at Rome.

Not until 1004 could the new German King Henry II of Germany, by the aid of Bishop Leo of Vercelli, move into Italy to have himself crowned rex Italiae.

[13] Henry's Salian successor Conrad II tried to confirm his dominion against Archbishop Aribert of Milan and other Italian aristocrats (seniores).

While besieging Milan in 1037, he issued the Constitutio de feudis in order to secure the support of the vasvassores petty gentry, whose fiefs he declared hereditary.

The cities first demonstrated their increasing power during the reign of the Hohenstaufen Emperor Frederick Barbarossa (1152–1190), whose attempts to restore imperial authority in the peninsula led to a series of wars with the Lombard League, a league of northern Italian cities, most of the times headed by Milan, and ultimately to a decisive victory for the League at the Battle of Legnano in 1176, that had as its leader the Milanese Guido da Landriano, which forced Frederick to make administrative, political, and judicial concessions to the municipalities, officially ending his attempt to dominate Northern Italy.

[14][15] The scene was similar to that which had occurred between Pope Gregory VII and Henry IV, Holy Roman Emperor at Canossa a century earlier.

Henry restored the rule of Matteo I Visconti and proceeded to Rome, where he was crowned emperor by three cardinals in place of Pope Clement V in 1312.

His further plans to restore the Imperial rule in northern Italy and to expand the empire, invading the Kingdom of Naples, were aborted by his sudden death the next year.

The Imperial claims to dominion in Italy mostly manifested themselves, however, in the granting of titles to the various strongmen who had begun to establish their control over the formerly republican cities.

By the beginning of the early modern period, the Kingdom of Italy still formally existed but had de facto splintered into completely independent and self-governing Italian city-states.

Its territory had been significantly limited – the conquests of the Republic of Venice in the "domini di Terraferma" and those of the Papal States had taken most of northeastern and central Italy outside the jurisdiction of the Empire.

Furthermore, the Imperial rights were notably asserted during the Italian Wars by Charles V, Holy Roman Emperor (also king of Spain, Naples and archduke of Austria).

However, following the reign of Charles V, no Holy Roman Emperor of the Austrian Habsburgs was crowned king of Italy and the title effectively ceased to be used for two centuries and a half.

[21][22] In 1559, the Kingdom of France ended its ambitions over the Imperial fiefs in Italy, abandoning its claims to Savoy and Milan and withdrawing from Tuscany and Genoese Corsica by the terms of the Treaty of Cateau-Cambrésis.

The Italian states were in large part autonomous, but their lack of representation gave the emperor greater ability to act more autonomously with the Italian principalities than the German ones, such as when he decided to simply add the Grand Duchy of Tuscany (officially an imperial fief) to his family's lands after the extinction of the Medici ruling line in 1737.

Emperor Leopold I increasingly asserted his rights over the imperial fiefdoms of Italy from the 1660s with the decline of Spanish power and more overt intervention of the French.

In 1687, a new plenipotentiary of Italy was appointed, a position that had been left vacant for over a century prior (the powers of the office had instead been exercised haphazardly by the Aulic Council).

Then, in 1696, Leopold issued an edict mandating all of his Italian vassals to renew their oaths of allegiance within a year and a day on pain of forfeit.

Piedmont-Savoy, on the other hand, remained defiant of Imperial authority despite officially participating in the diet and the duke receiving the title of "Royal Highness" from the Emperor in 1693.

There was even a serious push by the Savoyards (backed by Prussia) to raise Savoy to electorate status in 1788, which would make it only the second non-German state to become so (after Bohemia, which was after the crushing of Bohemian estates in 1620 dominated by German-speaking aristocrats).

The Congress of Vienna following Napoleon's defeat did not bring back the Holy Roman Empire nor the Kingdom of Italy,[35][36] and the restored Italian duchies now became fully sovereign in their own right.